Answer:
                  Acid                                     base
Red litmus - color doesn't change   Color change to blue  
Blue litmus- color change to red.    Color
                                               doesn't change
Explanation:
Hope this helps
 
        
                    
             
        
        
        
Answer: Do you have answer choices?
Explanation:
 
        
             
        
        
        
Physical structures..........
        
             
        
        
        
I think it is A because they can just destroy it but D is finding something natural to kill it off but it is GM so it wouldn't help so A